Method and apparatus for presentation of on-line directional sound

ABSTRACT

There is disclosed an omnipresent sound system for use by a listener in an artificial reality system which operates to couple sound with the presented objects such that as the sound moves with respect to the user, the user will have the perception of the changing sound both in pitch and in volume. The sound system is comprised of a series of piezoelectric elements spaced apart around a user&#39;s head. The system is designed to program each element individually so as to create the illusion of omnipresent three-dimensional sound in conjunction with images presented to the listener, which images define an artificial environment.

TECHNICAL FIELD OF THE INVENTION

This invention relates to sound systems and more particularly to suchsystems that present sound to a listener in a "full wrap-around" manner.

CROSS REFERENCE TO RELATED APPLICATIONS

The following patent applications are cross-referenced to one another,and all have been assigned to Texas Instruments Incorporated. Theseapplications have been concurrently filed and are hereby incorporated inthis patent application by reference.

    ______________________________________                                        U.S. Pat. application                                                         Ser. No.    Filed    Title                                                    ______________________________________                                        593,196     10/05/90 Method and Apparatus for Provi-                                               ding a Portable Visual Display                           593,823     10/05/90 Method and Apparatus for Moni-                                                toring Physical Positioning of                                                a User                                                   ______________________________________                                    

BACKGROUND OF THE INVENTION

There are many situations in which full wrap-around sound is desirablefor presentation to a listener. One such system is in artificial realitysystems where an artificial environment has been created for a user.This environment would typically contain scenes that are createdsurrounding the viewer, and as the viewer moves in any plane relative tothe environment, the scene changes as it would if the viewer were movingin a real environment.

In some situations sound is presented to the viewer in conjunction withthe projected images such that as the viewer (or sound source) movescloser or further away, the sound will increase or decrease in volumeand frequency. At times the sound would appear to come from directlybehind, over or below the listener.

Conventional stereophonic speakers which are placed over each ear canonly approximate the direction of the sound from one side or the other.These speakers are expensive and do not satisfy the requirement that thelistener actually hear the sound coming from behind, above, below orfrom one side.

Currently, surround sound or holographic sound or what is called 3-Dsound, is generated by using powerful digital signal processors whichare basically stereo earphones tricking the ear into perceiving that thesound is coming from behind, around, or from different distances.

Thus, a need exists in the art for a speaker system which islightweight, inexpensive and yet which can create the illusion of soundcoming from an omnipresent direction.

There is a further need in the art for such a system which can becreated and controlled by an artificial reality system and is portableand generatable under processor control.

SUMMARY OF THE INVENTION

An omnipresent sound system has been constructed using a series ofdiscreet piezoelectric elements in a headband around the user's head.Each element is individually controllable from signals provided to itfrom the processor. Thus, sound can be programmed to occur at anyposition around the user's head.

By judiciously selecting the volume and timing of the sounds from eachof the individual piezoelectric elements, the listener will have thesensation of omnipresent stereographic sound which is keyed to the scenebeing viewed by the viewer in the artificial reality system. The scenebeing viewed is, in turn, controllable by the sensed motion of the user.

Thus, for example, a user can be walking (in the artificially createdenvironment) toward a siren (for example, a flashing light on avehicle), and the scene of the siren source (vehicle) would be gettinglarger. Concurrently, the sound from the siren would become louder, andthe frequency of the siren could also be changing depending upon theapproach angle. Of course, the vehicle could be moving relative to theviewer and the sound would change accordingly.

The system to create this illusion of changing sound is designed to sendsignals to different ones of the piezoelectric elements from time totime to create the illusion of the sound moving. These sound attributesof the created environment are stored in a portable processor andprovided to the viewer in conjunction with the proper scene. Thus, thesystem knows how far the viewer is from an object so it, in turn, knowswhich one of the piezoelectric elements to turn on. The system knowsthat as the viewer approaches to view objects, the sound should getlouder. If the viewer is looking directly at an object, the sound shouldcome from in front. The viewed objects can also have boundary boxesaround them so if the viewer moves into the object, a bump can be heard.In addition, the piezoelectric devices can be made to physicallyvibrate, thereby creating the "feeling" of sound impacting the viewer.

Since the system is object oriented, the closer the viewer gets to anobject, the more the sound will change. This is important forapplications, such as military and flight simulations.

Thus, it is a technical advantage of the invention to provide a soundsystem which is omnipresent with respect to a viewer and which islightweight and inexpensive to manufacture.

It is a further technical advantage of this invention that such a systemis designed to respond to signals provided by a portable processor andgenerated in conjunction with an artificial reality system to providesound in coordination with the derived physical presentation of theenvironment around the viewer.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention may be acquiredby referring to the detailed description and claims when considered inconnection with the accompanying drawings in which like referencenumbers indicate like features wherein:

FIG. 1 is a helmet mounted virtual reality device with the speakerelements exposed;

FIG. 2 is also a helmet mounted virtual reality device;

FIG. 3 is a schematic representation of a simulated reality system;

FIGS. 4a, 4b and 4c depict a CCD position-orientation sensor in variousorientations;

FIG. 5 shows a three-dimensional position-orientation sensor;, and

FIG. 6 shows a schematic of a system with a plurality of interconnectedvirtual reality devices.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 depicts a portable virtual reality system 10 worn by anindividual on his or her head. System 10 consists of a color liquiddisplay screen 101, an array of piezoelectric film elements 102, aposition-orientation sensor 12 and a processor 13.

Processor 13 generates a visual picture according to helmet 10orientation information from position-orientation sensor 12 and on boardsoftware. Processor 13 creates a three dimensional environment andprojects a view of it on screen 101. As the user moves his/her head and,hence, helmet 10, processor 13 changes the image on screen 13 to mimicthe view the user would perceive if he/she were actually in the threedimensional environment. Similarly, if the user walks or runs to a newlocation, processor 13 changes the image on screen 101 as if the userwalked or ran the same distance and direction in the three dimensionalenvironment.

Note that while screen 101 is a color liquid crystal display, it can beany type of display and can, for example, be positioned close to auser's eyes with a short focal length.

Processor 13 also generates a sound field through piezoelectric elements102 of sound band 11. Individual elements 102 are separately driven byprocessor 13. The processor selectively powers piezoelectric filmelements 102 on an individual basis to create a directional sound field.By doing so, the processor can create the illusion of a moving soundsource and of a stationary sound source when the user's head or bodymoves. The sound source would be stationary, i.e., the same sound wouldcontinue to come from the same elements when the user stops moving. Thesound elements can be small chips or elongated bands, each driven by aseparate signal from the processor.

FIG. 2 shows a system in which the user, using control 21, manuallychanges the presented image or manually creates a change in direction orspeed with respect to the created environment. Band 22 contains elements102 and can be adjusted via tightening mechanism 20, which can also be avolume control for the elements.

FIG. 3 schematically depicts processor 13, screen 101, speaker elements11, joystick 21, position-orientation sensor 12 and direction controlmodule 306. Processor 13 takes graphic information stored in a data baseand generates images that are displayed on screen 101. Processor 13 alsogenerates sound projected from piezoelectric film segments 102.Processor 13 could be a single processor or multiple processors such asa graphics processor from the TMS340 series and a digital signalprocessor from the TMS320 series, all available from Texas InstrumentsIncorporated. The '340 generates images shown on screen 101 and the '320generates sound on element band 11. Connected to processor 13 is aposition-orientation sensor 12. Position-orientation sensor 12 sensesthe direction that the user is looking. A flux gate compass (not shown)may also be linked to processor 13 to provide absolute north-southorientation information. Direction control block 306 provides processor13 with information indicating the user's location and view within thethree dimensional environment. Direction control block 306 receives userorientation information from position sensor 12 through processor 13 andfrom the user directly through joystick 21. Direction control block 306can determine the user's position within the three dimensionalenvironment by mathematically integrating the instantaneous orientationinformation from position-orientation sensor 12.

FIGS. 4a, b and c depict an element in an embodiment of a position andorientation sensor 12. Container 40 is fluid filled and has light source43 (or other source of electronic signals such as infrared or microwave)on one side and CCD 44 ("charge coupled device") or other electronicsignal detectors on the other. CCD 44 is able to sense where light 401impinges on it from source 43 and when light is blocked by fluid 42.FIGS. 4b and 4c depict different orientations of assembly 40 and hencedepict different levels of fluid in device 40.

In FIG. 4b as assembly 40 is tilted down, a larger area of CCD 44 isblocked by fluid 42, allowing less light 401 to strike CCD 44. Theamount of light impacting CCD 44 can be detected, for example, by usingan array of individual CCD (or other detectors) devices, and monitoring,perhaps on a digital basis, the light level. When horizontal, no lightgets through to CCD 44. In FIG. 4c fluid completely covers CCD 44.

In FIG. 5 a number of CCD assemblies 40 can be combined to indicate thetilt in different axes. Three assemblies, 40a, 40b and 40c are alignedalong mutually orthogonal axes and encapsulated in direction sensor 12to detect motion in three dimensions. The orientation information fromassemblies 40a, 40b and 40c is transmitted through cable 301 toprocessor 13. The CCD assemblies can also provide information on themotion and position of sensor 12 by examining the output of CCD deviceover time.

FIG. 6 shows a schematic of a system with a plurality of interconnectedvirtual reality devices 10A, 10B and 10N. Although this schematic showsonly three virtual reality devices 10, a person skilled in the art willrealize that there is no limit on how many such devices areinterconnected. Each virtual reality device 10 is connected to a viewerand is operable to provide an artificial viewing environment for thisviewer. Each of the virtual reality devices 10 include the elementsshown in FIGS. 1 through 5, for example processors 13A through 13N,which correspond to processor 13 in FIGS. 1, 2, 3 and 5. Each processor13A through 13N is operable to accept data from the viewer to which itis connected as well as from other viewers. Each virtual reality device10 presents on its screen 101 an artificial viewing environment to itslocal viewer based upon the data accepted from the local viewer as wellas the data accepted from other viewers. The virtual reality device 10is operative to coordinate the provision of impulse signals to itspiezoelectric elements 102 to create a sound field based on data bothfrom the local viewer and from the other viewers. The artificialenvironment and impulse signals presented to each viewer is unique tothat viewer and contains predefined structures.

It is possible to use only two devices to obtain all three orientationsby taking into account the slope of liquid within each device 40.

Although this description describes the invention with reference to theabove specified embodiments, it is but one example, and the claims, notthis description, limit the scope of the invention. Variousmodifications of the disclosed embodiment, as well as alternativeembodiments of the invention, will become apparent to persons skilled inthe art upon reference to the above description. Therefore, the appendedclaims will cover such modifications that fall within the true scope ofthe invention.

What is claimed is:
 1. A sound system for use in creating the illusionof holographic sound in an artificial reality system, said sound systemcomprising:a headband to be worn by a listener; at least three discretevibrationary elements placed circumferentially around said headband,each of said at least three discrete vibrationary elements adapted forreceiving electrical impulse signals and for producing sound waves inresponse thereto; and a processor for coordinating said impulse signalsand said at least three discrete elements such that said vibrationaryelements produce a directional sound field.
 2. The system set forth inclaim 1, wherein said at least three discrete vibrationary elements arepiezoelectric strips.
 3. The sound system as set forth in claim 1,wherein said artificial reality system is operable for creating anartificial viewing environment for a viewer, said artificial viewingenvironment including predefined structures, said artificial realitysystem comprising:a geographical sensor connectable to said viewer forproviding data corresponding to the relative movement of said viewer;said processor being dedicated to said viewer for accepting said datafrom said viewer; a presentation media for providing views of saidcreated artificial viewing environment to said viewer, said viewscontrolled by said processor and dependent upon said accepted data fromsaid viewer; and wherein said processor is operative for coordinatingsaid impulse signals and said at least three discrete vibrationaryelements in association with said provided views to said viewer.
 4. Asystem for creating artificial viewing environments for a firstindividual and a second individual, each of said artificial viewingenvironments including predefined structures, said system comprising afirst artificial reality system comprising:a headband to be worn by saidfirst individual; at least three discrete vibratory elements placedcircumferentially around said headband, each of said at least threediscrete vibratory elements adapted for receiving electrical impulsesignals and for producing sound waves in response thereto, and whereinsaid sound waves produce a directional sound field; a first geographicalsensor connectable to said first individual for providing datapertaining to the relative movement of said first individual; at leastone second geographical sensor connectable to said second individual forproviding data pertaining to the relative movement of said secondindividual; a first processor dedicated to said first individual foraccepting said data from said first individual and from said secondindividual; a presentation media for providing views of said createdartificial viewing environment to said first individual, said viewsbeing controlled by said first processor and being dependent upon saidaccepted data from said first individual and said data from said secondindividual; and wherein said first processor is operative forcoordinating said impulse signals and said at least three discretevibratory elements in association with said provided views to said firstindividual.
 5. The system set forth in claim 4, wherein said artificialviewing environment for said first individual is created by said firstprocessor and wherein artificial viewing environment and said impulsesignals for said first individual is unique to said first individual,with respect to said second individual.
 6. A method of creating a soundsystem comprising the steps of:placing a headband around the head of afirst individual; distributing at least three discrete vibratoryelements circumferentially around said headband, each of said at leastthree discrete vibratory elements adapted for receiving electricalimpulse signals and for producing sound waves in response thereto suchthat said sound waves produce a directional sound field.
 7. The methodas set forth in claim 6, wherein said method further comprises the stepof:providing electrical impulses to at least one of said at least threediscrete vibratory elements in accordance with the direction of originfrom which a particular sound is to be perceived by said firstindividual.
 8. The method as set forth in claim 7, wherein said at leastthree discrete vibratory elements are piezoelectric elements.
 9. Themethod as set forth in claim 6, wherein said method further comprisesthe step of coordinating via a processor integral with said headband,said impulse signals and said at least three discrete vibratoryelements.
 10. The method as set forth in claim 6, wherein said methodfurther comprises the step of:associating said sound with an artificialreality system operable for creating artificial viewing environments forsaid first individual and a second individual, each of said environmentsincluding predefined structures.
 11. The method as set forth in claim10, wherein said method further comprises the steps of:connecting ageographical sensor to each of said first and second individuals forproviding data pertaining to the relative movement of said first andsecond individuals; accepting, via a processor local to each of saidfirst and second individuals, said data from said first individual andfrom said second individual; and providing views of said createdartificial viewing environments to each of said first and secondindividuals, said views being controlled by said processor andcorresponding to said accepted data from said first individual and datafrom said second individual.
 12. The method as set forth in claim 10,wherein said method further comprises the step of creating saidartificial environment for each of said individual by said processor andwherein the environment and said impulse signals for each saidindividual is unique to said individual.